U.S. patent application number 10/528643 was filed with the patent office on 2006-09-28 for variable nozzle device for a turbocharger and method for operating the same.
Invention is credited to Raphael Hettinger, Alexis Lavez, Alain Lombard, Emmaruel Severin.
Application Number | 20060216141 10/528643 |
Document ID | / |
Family ID | 32104587 |
Filed Date | 2006-09-28 |
United States Patent
Application |
20060216141 |
Kind Code |
A1 |
Lavez; Alexis ; et
al. |
September 28, 2006 |
Variable nozzle device for a turbocharger and method for operating
the same
Abstract
A variable nozzle device (1) for a turbocharger comprises an
annular nozzle (3) formed between an inner wall (11) and an outer
wall (10), and an annular arrangement of adjustable vanes (4)
interposed in the nozzle (3) for defining a plurality of nozzle
passages, wherein the nozzle (3) is adjustable by controllably
adjusting the vanes (4) and by controllably varying an axial
clearance between the outer wall (10) and the vanes (4).
Inventors: |
Lavez; Alexis;
(Thaon-les-Vosges, FR) ; Lombard; Alain; (Thaon
Las Vosges, FR) ; Severin; Emmaruel; (Thaon Les
Vosges, FR) ; Hettinger; Raphael; (Thaon Les Vosges,
FR) |
Correspondence
Address: |
HONEYWELL TURBO TECHNOLOGIES
23326 HAWTHORNE BOULEVARD, SUITE #200
TORRANCE
CA
90505
US
|
Family ID: |
32104587 |
Appl. No.: |
10/528643 |
Filed: |
September 18, 2002 |
PCT Filed: |
September 18, 2002 |
PCT NO: |
PCT/IB02/03834 |
371 Date: |
May 19, 2006 |
Current U.S.
Class: |
415/159 |
Current CPC
Class: |
F01D 17/143 20130101;
F05D 2220/40 20130101; F01D 17/165 20130101 |
Class at
Publication: |
415/159 |
International
Class: |
F01D 17/12 20060101
F01D017/12 |
Claims
1. A variable nozzle device (1) for a turbocharger comprising: an
annular nozzle (3) formed between an inner wall (11) and an outer
wall (10), and an annular arrangement of adjustable vanes (4)
interposed in the nozzle (3) for defining a plurality of nozzle
passages, wherein the nozzle (3) is adjustable by controllably
adjusting the vanes (4) and by controllably varying an axial
clearance between the outer wall (10) and the vanes (4).
2. A variable nozzle device (1) according to claim 1, wherein the
outer wall (10) is axially moved to and from the vanes (4) by an
actuator, preferably a pneumatic actuator (6).
3. A variable nozzle device (1) according to claim 2, wherein the
axial movement of the outer wall (10) to the vanes (4) is limited
by a spacer which defines a minimum axial clearance between the
vanes (4) and the outer wall (10).
4. A variable nozzle device (1) according to any one of claims 1 to
3, wherein the outer wall (10) is defined by a hollow shaft (5)
which comprises an axial slit forming a bypass for exhaust gas
which does not pass through the nozzle (3).
5. A variable nozzle device (1) according to any one of claims 2 to
4, comprising means for operating the axial movement of the outer
wall (10) in such a manner that the outer wall (10) is moved away
from the vanes (4) as an operational rotational speed of the
turbocharger increases.
6. A variable nozzle device (1) according to any one of claims 2 to
5, comprising means for operating the axial movement of the outer
wall (10) in such a manner that the outer wall (10) is moved to the
vanes (4) as an operational rotational speed of the turbocharger
decreases.
7. A method for operating a variable nozzle device (1) for a
turbocharger comprising a plurality of vanes (4) arranged in a
nozzle (3) defined between an inner wall (11) and an outer wall
(10), the vanes (4) forming nozzle passages, the method comprising
the steps of: adjusting the nozzle passages by controllably
adjusting the vanes (4), and varying an axial clearance between the
outer wall (10) and the vanes (4) by axially moving the outer wall
(10) to and from the vanes (4).
8. A method for operating a variable nozzle device (1) for a
turbocharger according to claim 7, characterized by the following
steps: increasing the axial clearance between the outer wall (10)
and the vanes (4) as the operational rotational speed of the
turbocharger increases; and decreasing the axial clearance between
the outer wall (10) and the vanes (4) as an operational rotational
speed of the turbocharger decreases.
9. A method for operating a variable nozzle device (1) for a
turbocharger according to claim 7 or 8, wherein the step of
increasing the axial clearance between the outer wall (10) and the
vanes (4) starts and/or stops either independently from or
simultaneously with a step of pivoting the vanes (4) for enlarging
the gas flow area of the annular nozzle (3); and/or the step of
decreasing the axial clearance between the outer wall (10) and the
vanes (4) starts and/or stops either independently from or
simultaneously with a step of pivoting the vanes (4) for reducing
the gas flow area of the annular nozzle (3).
10. A vane pivoting mechanism for a variable nozzle device (1) of a
turbocharger comprising: at least one vane (4) attached to a gear
(7) and a gear device (8) being in engagement with the gear (7) so
that the vane (4) is pivoted when the gear device (8) is moved
relatively to the gear (7).
Description
[0001] The present invention generally relates to a variable nozzle
device for a turbocharger, and also to a method for operating a
variable nozzle device for a turbocharger.
[0002] A turbocharger having a conventional variable nozzle device
is known from U.S. Pat. No. 4,643,640. The nozzle device comprises
an annular nozzle between an inner wall and an outer wall, and an
annular arrangement of adjustable vanes interposed in the nozzle
for defining a plurality of nozzle passages, wherein the nozzle is
adjustable by controllably pivoting the vanes between the inner and
outer walls.
[0003] Thereby, the nozzle passages vary the gas flow to the
turbine, i.e. the gas flow area of the annular nozzle. The annular
nozzle is formed by a nozzle ring which forms the inner wall, a
shroud which forms the outer wall, and the pivotable vanes. There
has to be a clearance or a gap between the pivotable vanes and the
shroud so as to hold the vanes pivotable. The size of such
clearance is usually limited to both ensure performance level and
prevent the vanes from sticking to the shroud.
[0004] It is the object of the present invention to provide a
variable nozzle device for a turbocharger and a method for
operating a variable nozzle device which allow an improved turbine
performance.
[0005] This object is achieved by a variable nozzle device having
the features of claim 1 or 10, and by a method of operating a
variable nozzle device having the features of claim 7. The
invention is further developed by the dependent claims.
[0006] FIG. 1 shows a partial cross-section of a nozzle device for
a turbocharger according to a first embodiment of the present
invention;
[0007] FIGS. 2A and 2B show a cross-sectional view and a plan view
of the nozzle device according to the first embodiment of the
present invention, respectively, wherein the nozzle is fully
closed;
[0008] FIGS. 3A and 3B show a cross-sectional view and a plan view
of the nozzle device for a turbocharger according to the first
embodiment of the present invention, respectively, wherein the
nozzle is half open;
[0009] FIGS. 4A and 4B show a cross-sectional view and a plan view
of the nozzle device for a turbocharger according to the first
embodiment of the present invention, respectively, wherein the
nozzle is fully opened;
[0010] FIG. 5 shows a view of a nozzle device including a vane
pivoting mechanism for a turbocharger according to a second
embodiment of the present invention; and
[0011] FIG. 6 shows another view of the vane pivoting mechanism
depicted in FIG. 5.
[0012] A first embodiment of a nozzle device 1 according to the
present invention is described with reference to FIG. 1.
[0013] The nozzle device 1 shown in FIG. 1 is to be incorporated in
a turbocharger. A conventional turbocharger comprises an exhaust
gas driven turbine 2 mounted to a rotatable shaft 12 having a
compressor impeller thereon, a turbine housing 19 forming a volute
therein for directing an exhaust gas flow from an engine (not
shown) to the turbine 2 through an annular nozzle 3. The annular
nozzle 3 is defined between an inner and an outer wall 11, 10.
Interposed in the nozzle 3, there is an annular arrangement of
adjustable vanes 4 for defining a plurality of nozzle passages. The
nozzle 3 is adjustable by controllably adjusting the vanes 4
between the inner and outer walls 11, 10 so as to vary the geometry
of the nozzle passages.
[0014] The vanes 4 are adjusted by means of a vane pivoting
mechanism which is described with reference to the figures. The
vane pivoting mechanism consists of a vane pin 15, a vane arm 17, a
nozzle ring 16, an unisson ring 14 and an actuating member 18. The
vane 4, the vane pin 15 and the vane arm 17 are rigidly connected
to each other. The nozzle ring 16 is stationary, while the main arm
18 is pivotable with respect to the unisson ring 14.
[0015] When the main arm 18 rotates the unisson ring 14, as it is
shown in FIGS. 3A and 3B, the vanes 4 are pivoted.
[0016] In this embodiment, the inner wall 11 of the nozzle ring 16
is formed by an annular ring-shaped plate. Preferably, the annular
ring-shaped plate acts like a heat shield. However, the inner wall
11 may also be formed by any part of the turbine housing.
[0017] The nozzle device 1 according to the invention comprises a
hollow shaft 5 (a hollow piston) surrounding the turbine 2 and
defining the outer wall 10 of the annular nozzle 3, the hollow
shaft 5 being axially movable to and from the vanes 4.
[0018] The hollow shaft 5 is used to cancel the functional gap
(right and left side of the vane 4) and increase the turbine stage
efficiency all along the engine range until pivoting vane 4 are
fully open, then the sliding piston 5 starts to open from the vane
top, increasing the passage width and turbine flow capacity, the
hollow shaft 5 will be axially moved away from the vanes 4 so as to
prevent the vanes 4 from sticking to the outer wall 10 defined by
the hollow shaft S.
[0019] In this construction, commonly known elements once required
in the prior art for adjusting the clearance to approximately zero
can be omitted.
[0020] The movement of the hollow shaft 5 is effected by an
actuator 6 which is, for instance, a pneumatic actuator.
[0021] Preferably, the hollow shaft 5 comprises an axial slit (not
shown) forming a bypass for exhaust gas which does not pass through
the annular nozzle 3.
[0022] Preferably, the nozzle device 1 is operated by means for
operating the hollow shaft 5 in such a manner that the hollow shaft
5 is moved away from the vanes 4 as an operational rotational speed
of the turbocharger increases, and that the hollow shaft 5 is moved
to the vanes 4 as the operational rotational speed of the
turbocharger decreases.
[0023] The operation of the nozzle device 1 will be explained below
in more detail with reference to the FIGS. 2A-2B, 3A-3B and
4A-4B.
[0024] As it is shown in FIGS. 2A and 2B, in a low rotational speed
range of the turbocharger, the nozzle passages are closed by the
vanes 4. At the same time, the hollow shaft 5 is initially in
contact with the vanes 4 so as to cancel the clearance between the
vanes 4 and the walls 10. Thereby, the turbine stage exhibits a
improved efficiency even in the low rotational speed range of the
turbocharger.
[0025] As it is shown in FIGS. 3A and 3B, in medium rotational
speed ranges, the nozzle passages are opened by the vanes 4 by
pivoting the vanes 4, but the hollow shaft 5 is still kept in the
position close to the vanes 4. Thereby, the nozzle is
half-opened.
[0026] As it is shown in FIGS. 4A and 4B, in high rotational speed
ranges, the nozzle passages are further kept open by the vanes 4.
At the same time, the hollow shaft 5 is moved away from the vanes
4. Thereby, the vanes 4 are prevented from sticking on the outer
wall 10 defined by the hollow shaft 5.
[0027] Advantageously, the flow capacity is increased such that an
engine backpressure in the high rotational speed range of the
turbine 2 is reduced.
[0028] If the hollow shaft 5 is additionally provided with the slit
for forming the bypass, the flow capacity is further increased such
that the engine backpressure in the high rotational speed range of
the turbine 2 is further reduced.
[0029] The timing of moving the hollow shaft 5 and the timing of
pivoting the vanes 4 may be tuned so as to achieve an optimum
performance of the turbocharger, i.e. an optimum turbine
efficiency, a large boost and a low backpressure. As it is
described above, when the rotational speed increases, the vanes 4
are first adjusted to open the nozzle passages. When the rotational
speed is further increased, the hollow shaft 5 is then moved away
from the vanes 4.
[0030] In general, it is possible to start moving the hollow shaft
5 away from the vanes 4 and to start pivoting the vanes 4 for
enlarging the gas flow area of the annular nozzle 3 either
independently (separately) or simultaneously. It is also possible
to start moving the hollow shaft 5 to the vanes 4 and to start
pivoting the vanes 4 for reducing the gas flow area of the annular
nozzle 3 either independently or simultaneously.
[0031] In a similar manner, it is possible to stop moving the
hollow shaft 5 away from the vanes 4 and to stop pivoting the vanes
4 for enlarging the gas flow area of the annular nozzle 3 either
independently or simultaneously, and/or to stop moving the hollow
shaft 5 to the vanes 4 and to stop pivoting the vanes 4 for
reducing the gas flow area of the annular nozzle 3 either
independently or simultaneously.
[0032] The first embodiment can be modified in that, instead of the
hollow shaft 5, any means can be provided which comprises a
variable outer wall for varying the gas flow to the turbine.
[0033] The embodiment according to the present invention achieves a
large boost in the low rotational speed range due to the cancelled
clearance (also called "zero gap") between the vanes 4 and the
outer wall 10 defined by the hollow shaft 5, when the hollow shaft
5 is in a position closest to the vanes 4.
[0034] In middle and high rotational speeds of the engine, the
backpressure is reduced by moving the hollow shaft 5 away from the
vanes 4. The backpressure may be further decreased by the bypass
for exhaust gas, which does not pass through the annular nozzle
3.
[0035] A second embodiment according to the present invention shows
a nozzle device including a vane pivoting mechanism as it is
described with reference to FIGS. 5 and 6.
[0036] The vane pivoting mechanism for a variable nozzle device 1
for a turbocharger comprises at least one vane 4 attached to a gear
7 and a gear device 8 being in engagement with the gear 7 so that
the vane 4 is pivoted when the gear device 8 is moved relatively to
the gear.
[0037] Preferably, the vanes 4 are connected via a rod (not shown)
with the respective gear wheels 7. The rods pass through the inner
wall 11 such that they are rotatably supported by the inner wall
11. For pivoting the vanes 4, there are two alternative modes. In
the first mode, the inner wall 11 is rotated while the gear ring 8
is fixed. In the second mode, the gear ring 8 is rotated while the
inner wall 11 is fixed.
[0038] The provision of the gear wheels 7 and the gear ring 8 for 5
pivoting the vanes 4 is simpler than the prior art arrangement,
since many elements can be omitted which were necessary in the
prior art, for instance arm vanes, rollers, pins, unisson rings,
etc.
[0039] Instead of the gear wheel 7, any element having a gear or a
toothing can be provided. It is further conceivable that the gears
7 and the ring 8 are in a frictional engagement instead of a
meshing engagement.
[0040] The embodiments described herein are to be considered as
illustrative and they do not limit the scope of protection. The
invention can be modified within the scope of the attached
claims.
* * * * *